org.apache.hive.hcatalog.templeton.tool.TrivialExecService.java Source code

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Here is the source code for org.apache.hive.hcatalog.templeton.tool.TrivialExecService.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.hive.hcatalog.templeton.tool;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

/**
 * Execute a local program.  This is a singleton service that will
 * execute a programs on the local box.
 * 
 * Note that is is executed from LaunchMapper which is executed in 
 * different JVM from WebHCat (Templeton) server.  Thus it should not call any classes
 * not available on every node in the cluster (outside webhcat jar)
 */
final class TrivialExecService {
    private static final Log LOG = LogFactory.getLog(TrivialExecService.class);
    private static volatile TrivialExecService theSingleton;

    /**
     * Retrieve the singleton.
     */
    public static synchronized TrivialExecService getInstance() {
        if (theSingleton == null)
            theSingleton = new TrivialExecService();
        return theSingleton;
    }

    public Process run(List<String> cmd, List<String> removeEnv, Map<String, String> environmentVariables)
            throws IOException {
        LOG.info("run(cmd, removeEnv, environmentVariables)");
        LOG.info("Starting cmd: " + cmd);
        ProcessBuilder pb = new ProcessBuilder(cmd);
        for (String key : removeEnv) {
            if (pb.environment().containsKey(key)) {
                LOG.info("Removing env var: " + key + "=" + pb.environment().get(key));
            }
            pb.environment().remove(key);
        }
        pb.environment().putAll(environmentVariables);
        logDebugInfo("========Starting process with env:========", pb.environment());
        printContentsOfDir(".");
        return pb.start();
    }

    private static void logDebugInfo(String msg, Map<String, String> props) {
        StringBuilder sb = TempletonUtils.dumpPropMap(msg, props);
        LOG.info(sb.toString());
        String sqoopHome = props.get("SQOOP_HOME");
        if (TempletonUtils.isset(sqoopHome)) {
            //this is helpful when Sqoop is installed on each node in the cluster to make sure
            //relevant jars (JDBC in particular) are present on the node running the command
            printContentsOfDir(sqoopHome + File.separator + "lib");
        }
    }

    /**
     * Print files and directories in current {@code dir}.
     */
    private static StringBuilder printContentsOfDir(String dir, int depth, StringBuilder sb) {
        StringBuilder indent = new StringBuilder();
        for (int i = 0; i < depth; i++) {
            indent.append("--");
        }
        File folder = new File(dir);
        sb.append(indent).append("Files in '").append(dir).append("' dir:").append(folder.getAbsolutePath())
                .append('\n');

        File[] listOfFiles = folder.listFiles();
        if (listOfFiles == null) {
            return sb;
        }
        for (File fileName : listOfFiles) {
            if (fileName.isFile()) {
                sb.append(indent).append("File: ").append(fileName.getName()).append('\n');
            } else if (fileName.isDirectory()) {
                printContentsOfDir(fileName.getName(), depth + 1, sb);
            }
        }
        return sb;
    }

    private static void printContentsOfDir(String dir) {
        LOG.info(printContentsOfDir(dir, 0, new StringBuilder()).toString());
    }
}